Security personnel fanned out across the states, where a ground-to-air security apparatus was put in place on the eve of Republic Day amid a call by rebel groups in the northeast for boycott of all celebrations.

Shivaji Park ground in central Mumbai where Republic Day celebrations will be held, was declared a 'no flying zone' by the DGCA due to Intelligence inputs which suggested that terrorists might attempt air strikes, police said.

The area has not only been declared a 'No Flying Zone', but paragliding or use of remote-controlled microlight aircraft would also not be allowed, keeping in mind the possibility of terrorists using such methods to attack.

A bomb detection and disposal squad along with the local police will be stationed near the ground.

In the national capital, over 25,000 police personnel, including those from paramilitary and sharpshooters from
NSG, were deployed in the run-up to the celebrations, which will be attended by Bhutan king Jigme Khesar Namgyel
Wangchuck.

Snipers took positions at high-rise buildings while over 150 CCTVs kept a tight vigil on people's movement between Rajpath and Red Fort, the route of the parade which showcases India's military might and cultural diversity.

Mobile hit teams, anti-aircraft guns and sharpshooters of the NSG are also on the job at various places while paramilitary and Delhi Police commandos are keeping a close watch along the route of the
eight-kilometre long Republic Day parade from Raisana Hills to Red Fort.

A multi-layer security ring has already been put in place at Rajpath, where President Pranab Mukherjee will unfurl the tricolour and take the salute of marching contingents.

Security has been tightened across Assam and other northeastern states following the boycott call of R-Day celebrations by several militant groups. In Assam, a red alert has been sounded in view of Intelligence reports that ULFA along with Maoists may carry out subversive
activities.